fix: preserve partial tool failures

packages/cli/src/acp/event.ts

@@ -198,7 +198,7 @@ export async function streamTurn(input: {
             toolCallId: event.data.callID,
             toolName: current.name,
             input: current.input,
-            structured: event.data.structured ?? current.structured,
+            structured: event.data.metadata ?? current.structured,
             content: event.data.content ?? current.content,
             error: event.data.error.message,
             cwd: input.cwd,

packages/cli/src/run/noninteractive.ts

@@ -398,6 +398,8 @@ export async function runNonInteractivePrompt(input: Input) {
         const key = toolKey(event.data.assistantMessageID, event.data.callID)
         const current = tools.get(key) ?? fallbackTool(event)
         const error = event.data.error.message
+        const structured = event.data.metadata ?? current.structured
+        const content = event.data.content ?? current.content
         const tool: SessionMessageAssistantTool = {
           type: "tool",
           id: event.data.callID,
@@ -408,8 +410,8 @@ export async function runNonInteractivePrompt(input: Input) {
           state: {
             status: "error",
             input: current.input,
-            structured: event.data.structured ?? current.structured,
-            content: event.data.content ?? current.content,
+            structured,
+            content,
             error: event.data.error,
             result: event.data.result,
           },
@@ -439,14 +441,14 @@ export async function runNonInteractivePrompt(input: Input) {
         renderedTools.add(key)
         if (input.compatibility === "v1" && (permissionRejected || formCancelled)) continue
         if (!emit("tool_use", time, { part })) {
-          if (toolOutputText(current.tool, current.content).trim())
+          if (toolOutputText(current.tool, content).trim())
             await input.renderTool({
               ...tool,
               state: {
                 status: "completed",
                 input: current.input,
-                structured: current.structured,
-                content: current.content,
+                structured,
+                content,
                 result: event.data.result,
               },
             })

packages/cli/test/acp/event-behavior.test.ts

@@ -265,7 +265,7 @@ describe("acp event behavior", () => {
             assistantMessageID: "msg_tools",
             callID: "call_fail",
             error: { type: "tool.error", message: "not found" },
-            structured: { bytes: 0 },
+            metadata: { bytes: 0 },
             content: [{ type: "text", text: "opening" }],
             executed: true,
           }),

packages/cli/test/run/noninteractive.test.ts

@@ -148,7 +148,7 @@ function failedTool(inputID: string): V2Event[] {
         assistantMessageID: "msg_failed_tool",
         callID: "call_failed_tool",
         error: { type: "unknown", message: "tool failed" },
-        structured: { checkpoint: 1 },
+        metadata: { checkpoint: 1 },
         content: [{ type: "text", text: "partial output" }],
         executed: true,
       },
@@ -441,11 +441,11 @@ describe("runNonInteractivePrompt", () => {
     expect(output).toEqual({ stdout: "", stderr: "", exitCode: 0 })
   })
 
-  test("renders native failed tool output before the terminal error", async () => {
+  test("renders a native terminal failure snapshot when live progress was missed", async () => {
     const rendered: SessionMessageAssistantTool[] = []
     const failed: SessionMessageAssistantTool[] = []
     await capture({
-      turn: failedTool,
+      turn: (inputID) => failedTool(inputID).filter((event) => event.type !== "session.tool.progress"),
       renderTool: (part) => {
         rendered.push(part)
         return Promise.resolve()

packages/client/src/promise/generated/types.ts

@@ -1863,8 +1863,8 @@ export type SessionToolFailed = {
     assistantMessageID: string
     callID: string
     error: SessionStructuredError
-    structured?: { [x: string]: any }
-    content?: Array<LLMToolContent>
+    content?: [LLMToolContent, ...Array<LLMToolContent>]
+    metadata?: { [x: string]: any }
     result?: any
     executed: boolean
     resultState?: SessionMessageProviderState7

packages/core/src/session/message-updater.ts

@@ -402,7 +402,7 @@ export function update(adapter: Adapter, event: SessionEvent.Event) {
                 status: "error",
                 error: event.data.error,
                 input: typeof match.state.input === "string" ? {} : match.state.input,
-                structured: event.data.structured ?? (match.state.status === "running" ? match.state.structured : {}),
+                structured: event.data.metadata ?? (match.state.status === "running" ? match.state.structured : {}),
                 content: event.data.content ?? (match.state.status === "running" ? match.state.content : []),
                 result: event.data.result,
               }),

packages/core/src/session/runner/llm.ts

@@ -62,8 +62,6 @@ const layer = Layer.effect(
             assistantMessageID: message.id,
             callID: tool.id,
             error: { type: "aborted", message: `Tool execution interrupted: ${tool.name}` },
-            structured: tool.state.status === "running" ? tool.state.structured : {},
-            content: tool.state.status === "running" ? tool.state.content : [],
             executed: tool.executed === true,
           })
         }

packages/core/src/session/runner/publish-llm-event.ts

@@ -58,10 +58,14 @@ export const createLLMEventPublisher = (events: Pick<EventV2.Interface, "publish
       progress?: ToolRegistry.Progress
     }
   >()
-  const failureState = (tool: { readonly progress?: ToolRegistry.Progress }) => ({
-    structured: tool.progress?.structured ?? {},
-    content: tool.progress?.content ?? [],
-  })
+  const failureSnapshot = (tool: { readonly progress?: ToolRegistry.Progress }) => {
+    if (!tool.progress) return {}
+    const first = tool.progress.content[0]
+    return {
+      ...(first === undefined ? {} : { content: [first, ...tool.progress.content.slice(1)] as const }),
+      metadata: tool.progress.structured,
+    }
+  }
   let assistantMessageID = input.assistantMessageID
   let stepStarted = false
   let stepFailed = false
@@ -238,7 +242,7 @@ export const createLLMEventPublisher = (events: Pick<EventV2.Interface, "publish
         type: "tool.input-json",
         message: "Tool call arguments were malformed JSON and were not executed. Retry with valid JSON.",
       },
-      ...failureState(tool),
+      ...failureSnapshot(tool),
       executed: false,
     })
   })
@@ -263,7 +267,7 @@ export const createLLMEventPublisher = (events: Pick<EventV2.Interface, "publish
         assistantMessageID: tool.assistantMessageID,
         callID,
         error,
-        ...failureState(tool),
+        ...failureSnapshot(tool),
         executed: tool.providerExecuted,
       })
     }
@@ -423,7 +427,7 @@ export const createLLMEventPublisher = (events: Pick<EventV2.Interface, "publish
             assistantMessageID: tool.assistantMessageID,
             callID: event.id,
             error: result.error,
-            ...failureState(tool),
+            ...failureSnapshot(tool),
             result: event.result,
             executed,
             resultState,
@@ -456,7 +460,7 @@ export const createLLMEventPublisher = (events: Pick<EventV2.Interface, "publish
             event.message === `Unknown tool: ${event.name}`
               ? { type: "tool.unknown", message: event.message }
               : { type: "tool.execution", message: event.message },
-          ...failureState(tool),
+          ...failureSnapshot(tool),
           executed: tool.providerExecuted,
           resultState: providerState(event.providerMetadata),
         })

packages/core/test/session-runner-tool-events.test.ts

@@ -109,11 +109,21 @@ test("interrupted progress publication remains in the terminal failure snapshot"
   await Effect.runPromise(publisher.failUnsettledTools({ type: "aborted", message: "interrupted" }))
 
   expect(published.find((event) => event.type === "session.tool.failed.1")?.data).toMatchObject({
-    structured: { phase: "visible" },
+    metadata: { phase: "visible" },
     content: [{ type: "text", text: "visible" }],
   })
 })
 
+test("failure before progress omits partial output fields", async () => {
+  const { published, publisher } = capture()
+  await Effect.runPromise(publisher.publish(call))
+  await Effect.runPromise(publisher.failUnsettledTools({ type: "aborted", message: "interrupted" }))
+
+  const failed = published.find((event) => event.type === "session.tool.failed.1")?.data
+  expect(failed).not.toHaveProperty("content")
+  expect(failed).not.toHaveProperty("metadata")
+})
+
 test("provider metadata is flattened using the route key", async () => {
   const { published, publisher } = capture()
   await Effect.runPromise(

packages/core/test/session-runner.test.ts

@@ -892,7 +892,7 @@ describe("SessionRunnerLLM", () => {
     }),
   )
 
-  it.effect("persists the final progress snapshot when a tool fails", () =>
+  it.effect("persists the latest partial snapshot when a tool fails", () =>
     Effect.gen(function* () {
       const session = yield* setup
       const registry = yield* ToolRegistry.Service

packages/core/test/session-tool-progress.test.ts

@@ -22,10 +22,10 @@ const it = testEffect(LayerNode.compile(LayerNode.group([Database.node, EventV2.
 const timestamp = DateTime.makeUnsafe(1)
 const model = { id: ModelV2.ID.make("model"), providerID: ProviderV2.ID.make("provider") }
 
-const content = (text: string) => [{ type: "text" as const, text }]
+const content = (text: string) => [{ type: "text" as const, text }] as const
 
 describe("Tool.Progress", () => {
-  it.effect("keeps progress live-only and terminal settlements replayable", () =>
+  it.effect("keeps progress live-only and terminal settlements durable", () =>
     Effect.gen(function* () {
       const { db } = yield* Database.Service
       const service = yield* EventV2.Service
@@ -123,7 +123,7 @@ describe("Tool.Progress", () => {
         assistantMessageID,
         callID: "call-failed",
         error: { type: "unknown", message: "boom" },
-        structured: { phase: "checkpoint" },
+        metadata: { phase: "checkpoint" },
         content: content("before failure"),
         executed: false,
       })
@@ -149,7 +149,6 @@ describe("Tool.Progress", () => {
       expect(rows.map((row) => row.type)).not.toContain(EventV2.versionedType(SessionEvent.Tool.Progress.type, 1))
       expect(rows.map((row) => row.type)).toContain(EventV2.versionedType(SessionEvent.Tool.Success.type, 1))
       expect(rows.map((row) => row.type)).toContain(EventV2.versionedType(SessionEvent.Tool.Failed.type, 1))
-
     }),
   )
 })

packages/schema/src/session-event.ts

@@ -3,7 +3,7 @@ export * as SessionEvent from "./session-event.js"
 import { Schema } from "effect"
 import { optional } from "./schema.js"
 import { Event } from "./event.js"
-import { FinishReason } from "./llm.js"
+import { FinishReason, ToolContent } from "./llm.js"
 import { Model } from "./model.js"
 import { NonNegativeInt, PositiveInt, RelativePath } from "./schema.js"
 import { FileAttachment } from "./prompt.js"
@@ -409,15 +409,14 @@ export namespace Tool {
   })
   export type Called = typeof Called.Type
 
-  const ToolOutputFields = {
-    structured: SessionMessage.ToolStateRunning.fields.structured,
-    content: SessionMessage.ToolStateRunning.fields.content,
-  }
-
-  /** Live replacement snapshot for a running tool. Terminal events own durable output. */
+  /** Live replacement snapshot for a running tool. */
   export const Progress = Event.ephemeral({
     type: "session.tool.progress",
-    schema: { ...ToolBase, ...ToolOutputFields },
+    schema: {
+      ...ToolBase,
+      structured: Schema.Record(Schema.String, Schema.Unknown),
+      content: Schema.Array(ToolContent),
+    },
   })
   export type Progress = typeof Progress.Type
 
@@ -426,7 +425,8 @@ export namespace Tool {
     ...options,
     schema: {
       ...ToolBase,
-      ...ToolOutputFields,
+      structured: Schema.Record(Schema.String, Schema.Unknown),
+      content: Schema.Array(ToolContent),
       result: Schema.Unknown.pipe(optional),
       executed: Schema.Boolean,
       resultState: SessionMessage.ProviderState.pipe(optional),
@@ -440,9 +440,8 @@ export namespace Tool {
     schema: {
       ...ToolBase,
       error: SessionError.Error,
-      // Optional only for compatibility with existing v1 failure rows.
-      structured: ToolOutputFields.structured.pipe(optional),
-      content: ToolOutputFields.content.pipe(optional),
+      content: Schema.NonEmptyArray(ToolContent).pipe(optional),
+      metadata: Schema.Record(Schema.String, Schema.Unknown).pipe(optional),
       result: Schema.Unknown.pipe(optional),
       executed: Schema.Boolean,
       resultState: SessionMessage.ProviderState.pipe(optional),

packages/tui/src/context/data.tsx

@@ -643,7 +643,7 @@ export const { use: useData, provider: DataProvider } = createSimpleContext({
               status: "error",
               error: event.data.error,
               input: typeof match.state.input === "string" ? {} : match.state.input,
-              structured: event.data.structured ?? (match.state.status === "running" ? match.state.structured : {}),
+              structured: event.data.metadata ?? (match.state.status === "running" ? match.state.structured : {}),
               content: event.data.content ?? (match.state.status === "running" ? match.state.content : []),
               result: event.data.result,
             }

packages/tui/src/mini/stream-v2.subagent.ts

@@ -838,7 +838,7 @@ export function createSubagentTracker(input: SubagentTrackerInput): SubagentTrac
                 status: "error",
                 input: part && part.state.status !== "streaming" ? part.state.input : {},
                 structured:
-                  event.data.structured ?? (part && part.state.status !== "streaming" ? part.state.structured : {}),
+                  event.data.metadata ?? (part && part.state.status !== "streaming" ? part.state.structured : {}),
                 content: event.data.content ?? (part && part.state.status !== "streaming" ? part.state.content : []),
                 error: event.data.error,
                 result: event.data.result,
@@ -967,7 +967,7 @@ export function createSubagentTracker(input: SubagentTrackerInput): SubagentTrac
       const key = sourceKey(event.data.assistantMessageID, event.data.callID)
       const pending = pendingCalls.get(key)
       if (event.type !== "session.tool.progress") pendingCalls.delete(key)
-      const found = childSessionID(record(event.data.structured))
+      const found = childSessionID(record(event.type === "session.tool.failed" ? event.data.metadata : event.data.structured))
       if (!found) return
       const child = admitChild(found.sessionID)
       if (!child) return

packages/tui/src/mini/stream-v2.transport.ts

@@ -1085,7 +1085,7 @@ export async function createSessionTransport(input: StreamInput): Promise<Sessio
               status: "error",
               input: part && part.state.status !== "streaming" ? part.state.input : {},
               structured:
-                event.data.structured ?? (part && part.state.status !== "streaming" ? part.state.structured : {}),
+                event.data.metadata ?? (part && part.state.status !== "streaming" ? part.state.structured : {}),
               content: event.data.content ?? (part && part.state.status !== "streaming" ? part.state.content : []),
               error: event.data.error,
               result: event.data.result,

packages/tui/test/mini/stream-v2.transport.test.ts

@@ -2062,7 +2062,7 @@ describe("V2 mini transport", () => {
         assistantMessageID: "msg_progress",
         callID: "call_progress",
         error: { type: "unknown", message: "boom" },
-        structured: { checkpoint: 1 },
+        metadata: { checkpoint: 1 },
         content: [{ type: "text", text: "partial" }],
         executed: true,
       },
@@ -2892,8 +2892,7 @@ describe("V2 mini transport", () => {
         assistantMessageID: "msg_failed_subagent",
         callID: "call_failed_subagent",
         error: { type: "unknown", message: "subagent failed" },
-        structured: { sessionID: "ses_child_failed", status: "running" },
-        content: [],
+        metadata: { sessionID: "ses_child_failed", status: "running" },
         executed: true,
       },
     })
@@ -3032,7 +3031,7 @@ describe("V2 mini transport", () => {
         assistantMessageID: "msg_child_tool",
         callID: "call_child_shell",
         error: { type: "unknown", message: "child boom" },
-        structured: { checkpoint: "child" },
+        metadata: { checkpoint: "child" },
         content: [{ type: "text", text: "child partial" }],
         executed: true,
       },